Monolithic Plastic Rear Shell for Spray Gun Rigidity and Sealing

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Solution Overview

Problem

Existing spray guns face issues with powder dust penetration, electrostatic charging, ergonomic design, and rigidity, leading to inefficient handling and potential coating material deposition.

Innovation Solution

A monolithic plastic rear shell with a grip and cover area, integrated connecting elements, and ergonomic design enhances rigidity, sealing, and ergonomic grip security, while incorporating a grounding element to manage electrostatic charges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If multiple separate components are used to cover the rear area, then ease of manufacture is improved, but rigidity in bending and torsion deteriorates

Engineering Contradiction:
Improveease of manufactureVSAvoidrigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent combines multiple separate components (handle cover, rear cover, connecting elements) into a single monolithic plastic component manufactured via injection molding. This merging eliminates the need for multiple parts while simultaneously improving rigidity in bending and torsion, directly resolving the contradiction between ease of manufacture and structural strength.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of repair

If multiple separate components are used to cover the rear area, then ease of repair is improved, but sealing performance deteriorates

Engineering Contradiction:
Improveease of repairVSAvoidsealing performance
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

By merging the handle cover, rear cover, and connecting elements into one monolithic component, the patent eliminates interface areas where coating material could penetrate. This single-component design ensures optimal sealing while maintaining ease of repair through the simplicity of replacing one component rather than multiple separate parts.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If separate components with interfaces are used, then adaptability is improved, but coating material penetration increases

Engineering Contradiction:
ImproveadaptabilityVSAvoidcoating material penetration
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates interface areas by combining all rear covering components into one monolithic piece. This design prevents coating material (both powder and liquid) from penetrating through gaps between separate components, directly addressing the harmful effect while maintaining adaptability through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

4Device complexity

If separate components are used, then device complexity is reduced, but electrostatic charging risk increases

Engineering Contradiction:
Improvedevice complexityVSAvoidelectrostatic charging risk
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

By merging all rear components into a single electrically insulating plastic component, the patent minimizes the number of interfaces where electrostatic charging can occur. This reduces the risk of electrostatic discharge and improves safety while maintaining simplicity in the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

5Ease of manufacture

If non-ergonomic handle design is used, then manufacturing simplicity is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidergonomic grip
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies local quality by incorporating an ergonomically optimized grip area with specific surface geometry and texture in the monolithic component. This localized ergonomic design improves ease of operation without compromising the overall manufacturing simplicity of the injection-molded component.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The ergonomic handle design incorporates curved and contoured surfaces that adapt to the natural shape of the hand. These curvatures and transitions in the monolithic component provide comfortable gripping while maintaining the manufacturing advantages of injection molding.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution improves handling, minimizes coating material entry, and provides effective electrostatic discharge management, resulting in a more ergonomic and reliable spray gun design.

Implementation Method 1

the rear area of the spray gun, and in particular the area which connects the handle part of the spray gun to the gun barrel, can be made particularly rigid in terms of bending and torsion

Methodology Applied
Scientific EffectRigidity:

Implementation Method 2

the entire spray gun can be optimally sealed, as the interface areas through which coating material can pass are minimized

Methodology Applied
Scientific EffectSealing:

Implementation Method 3

These paths can lead to electrostatic charging of the coating material and electrically insulated gun parts

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Data Source

PatentEP3930913B1Rear bowl for a spray gun and spray gun with such a rear bowl
Publication Date: 2023.07.26 GEMA SWITZERLAND GMBH
  • EP3930913B1 patent drawingFigure 1~2
  • EP3930913B1 patent drawingFigure 3
  • EP3930913B1 patent drawingFigure 4

AI summary

The invention relates to a rear casing (10) for a spray gun (1), in particular a powder spray gun (1), wherein the spray gun (1) has a handle part (2) and a gun barrel (3) connected to the handle part (2). The rear casing (10) can be removeably and exhangeably attached to the rear side of a main body (4) of the spray gun (1) and has a first region designed as a handle casing (11) and a second region designed as a covering casing (12) for rear-side covering of a rear region of the gun barrel (3). At least one connection element (14) is provided on the second region of the rear casing (10) for optionally forming a removable connection to a part having, for this purpose, at least some portions with a design complementing that of said connection element. In particular, according to the invention, the entire rear casing (10), together with the at least one connection element (14), is designed as a monolithic plastic component, in particular a plastic injection moulded part.